M. Becerril, H. Silva-López, A. Guillén-Cervantes, O. Zela, and a-Ángel., “Aluminum-doped ZnO polycrystalline films prepared by co-sputtering of a ZnO-Al target”, Rev. Mex. Fís., vol. 60, no. 1 Jan-Feb, pp. 27–0, Jan. 2014.